August schrader



UNITED STATES PATENT ouron.

AUGUST scmmnnn, on NEW ,YORK, 1w. Y.

ACID AND WATER PROOF nix.

No Drawing.

To all whom it my concern: 1

Be it known that I, AUGUST SCHRADER, citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Acid and Water-Proof Ink, of which the following is a specification.

My invention relates to new and. useful improvements in writing fluids, the primary object being the provision of an acid and waterproof ink. In this connection, it-

should be noted that the. 'term acid ,proof ink is intended to fnerely express the fact that the inkis proof against acidsof the nature used in: alkcommercial ink eradi-' cators and not that itis proof against ex-- However, inas much as acids any stronger-than those used ceptionally strong acids.

in ink eradicators would injure the paper,

the ink will, ofcourse, be sufliciently acid.

proof to prevent successful tampering with any writing in which it has been employed. A furtherobject of my invention is the provision of'a water and acid proof 'ink' of the above described character which can be employed in fountain pens. t More specifically, my'improved .ink consists of 8 parts Silesian soluble'blue', l'p a'rt nigrosin, ,2 part 'oxalib" acid, part india.

ink, 290 parts wate v V The Silesian soluble'blue' employed is also knownaas Prussian blue'and the Although the above cdii'stitutes the pre- V ferred formula for my ink, it will of course be understood that slight changes in-pro- Specification of Letters Patent.

Patented Aug. 22, 1916.

Application filed November 8, 1915. Serial No. 60,421.

portions-of the various ingredients may be made if deemed advisable.

In making the ink according to the above formula, the india ink is first rubbed or ground down inthe usual manner and then.

steeped in a solution of the-oxalic acid until thoroughly dissolved. The nigrosin is then steeped in lukewarm water and after being dissolved in such water is strained. The resultantindia ink and oxalic acid solution and the resultant nigrosin solution are then .mixed together with the Silesian soluble ubleblue, nigrosin, oxalic acid, india ink 7 and water, the water constituting substantially twenty-ninethirtieths of the fluid. V 3. A writing .fluid including Silesian soluble .blue 8 parts, nigrosin 1 part, oxalic acid .2 part, india ink .8 part, and water .290 parts.

In testimony whereof I aifix mysignature in presence of two witnesses.

- AUGUST SOHRADER. [n s.]

Witnessesz H WILLIAM H.-DAVIS,

L-CHAS. J .Hown- 

